Wiring terminal connection for electrical wiring devices



July 1, 1952' HUBBELL WIRING TERMINAL CONNECTION FOR ELECTRICAL WIRING DEVICES Filed Jan. 10, 1947 Patented July 1, 1952 OFFICE WIRING TERMINAL CONNECTION FOR ELECTRICAL WIRING. DEVICES- Harvey Hubhell, Long Hill, Conn. A lication; January-10, 1947, Serial- No. 721,198

I 1.; v This invention relates tceleotrical wiring devices, such, for example aslswitches, receptacles andYthe-like, and more particularly. to ,the terminal connectionsforsuch.devices,.andihasioran object. toflprovide .animproved terminal. com nection for such devices.

Another object. .is to provide -.a terminal .conmotion for. suchdevices which permitslhothfront and back; wiringot a. lead wire. toJtheterm'inal.

A further object is. to. provide-a wiring. terminal in which it. isnot necessary to wrapthe lead wire, around. the. binding screw. inconnecting it to the terminal. a

A. still .further. object is toprovide a, terminal in. which. the hated endporti'on of a... lead lwire may be-tinsertedin the terminal while, the binding screw sis-retracted and then. clamped by merely tightening the screw.

Withthetforegoingpand other objects. in view, I have devised the xconstruction.illustrated in. the accompanying. drawing zformihg .a...p.ar.t.. of. this specification It. is, however, to he, understood the invention .isrnotflimitedi to. the specific .details. ofIconstruc-tionand. arrangement shown,

but may embody various. changes .andmodifications. within the scopeof, the invention.

In'thisdrawing: Y

. Fig. 1 isia'top plan view; ofan. electrical switch showing one ,form. of. myimproved wiring, terminal connection applied thereto;

, away to more. clearly show the construction;

Fig; 3 is a section on an enlarged soaleshowing a somewhat different construction of wiring terminal;

4 is a view looking toward1-the bottom of Fig. 3 with-the lower-member of the body removed'and'showing the terminal on "a somewhat larger scale, the view being taken substantially on the plane of the "line F-Mot "3-;

Fig: 5; is a bottom plarriviewof aportionof the upper partof the body-showing the recess in which the terminal is mounted;

Fig: 6 is --a vertical section-"throughthis :recess substantially ion the line "6-6; off Fig. 5;;

' Fig. "Tis-asection"through the bottom section ofthebody', and

Fig; 3 isa view simi-Iarto Fig. '3' showing an,- other somewhat "modified construction.

, In the drawings .the terminal is .shownas applied toa-switch construction, 'buti'hisis used merely byway of I examplagas the terminal connection is"equallypadapted'for'use in other electrical wiring devices, "such, "for example, as're- 3 Claims; (01. 173-259) end "216 of the rlead wire-pf conductor 2%;

ceptacles and the like, or any other electrical wiring device for which it is applicable.

In the .form ofthedevice shown. HLBfigs. 1 and the erminal connectioni shown a plied .to.-.a switchmounted. in a body, of insulatne material comprising. a ma n p rtion in and a...1iront portion. 1], the. por ion. .16 being pr videdwith a chamber l.2 whieh the switch mechanism is mountedn nclud ng th movable switch/member. 1.3; operatedby. a. to gle lever it. andmovable to. and; from. as a ionary on- 15; The section or. portion Ll. of; the body forms. a. corner. portion enclos n the open. iron sideofQtheehamher i2. a d issecured. to the main body. portion by. sui able mea s u h bein threadediintcit.

At the ..10I1,1 s de and a the oppos t end thehody. is. pr videdth rece se 1. n t

bottom: surface of." which ar mounted t e t r- .min'al l onnectionswy Thes each comprise. a base por ion 2.0, .in. this par i u ar. ca e. in. th form. of. a metal: p ate; se.cured to. the. bod :by screws '21 extending throu h the bod and .iihf fid 11 ,1 0 1 1 5 6 p'lates- E 0 p t arries theusual type ofh ndin -post scr w 22" thr aded into. the lea e. porti n, and n ludin a shank 23 extending rearvvardly ,from the base '29. At the inner edge of. the base portion '210 'is, the stationary contact .l-'5j, either .forming an integral part of the fbase portion or comprising a separate element secured ,tothe base portion.

'Rearward'l y or-under'thefbase portion Eflt'here isv provided an. inclined" glead wire, supporting surface arranged to cooperate with the shank of. the binding screw to .clampand secure ,the barred end' of a lead wire to the device. This inclined" surface may he provided on a Wai-l' of the insulatingflhooly or on a wall connected to the base portion in whichthe clampingscrew ismounted; In the arrangementof" 2; this "inclined surface is, on the insulating body. In

this case therear member 'Hl "isqprovided with an inclined wailor surface "24" located at one s de o a adjacent th ShaI kf 3 o h s rew. and the 'body' is provided with an opening 25 leadiirg-to thissurface insertion of the bared This inclined surface 214 islocate'd at one side of and adjacentthe shank of "the screw and is inclined to "the axis pit-the, shank; asshowni Fig. ;2,

so that when-the bared end -2-5of the leadwire device.

is inserted between this surface and the shank of the screw, it may be clamped between the shank and the surface, the inclined surface forming a supporting surface for the wire, while the wire is clamped by the shank of the screw on the opposite side of the wire. In making the connection, the bared portion of the wire may be inserted through the opening 25 as shown at the right hand end of Fig. 2, to a position between the shank of the screw and the inclined 1 surface 24, when the screw is retracted. Then the screw is threaded downwardly to clamp its inner free end portion against the bared wire, as shown in Fig. 2. This securely clamps the bared wire between the shank of the screw and the inclined surface 24, securely clamping the wire and making a very effective electrical con nection, and it will be seenthis connection can be made without winding the bare portion of the wire around the clamping screw under the head of the screw, as in the usual terminal connection, although the wire may be so connected if desired.

As the material of the body I?! is usually made of some type of molded insulating material, it might have a tendency to crack under the pressure of the screw in clamping the wire. To form a reinforcement to reduce the strain on this material the base portion 29 of the terminal may be extended over the inclined wall 24 and provided with an opening 28 in substantial alignment with .the surface, so that the free end portion of the wire is passed through and seats in this opening,

as shown at 29. With this arrangement, part of the strain is carried by the metal base portion 29 of the terminal, relieving the pressure on the molded material of the body. It will be seen from this arrangement that the lead wire may be inserted from the back of the body or wiring device and clamped by merely setting the clamping screw, the screw shank together with the inclined surface 24 having a wedging action on the bared portion of the wire, which will effectively clamp it and prevent its being drawn out of the wiring However, with this arrangement the bared wire may be inserted from the front, as

shown at the left hand of Fig. 2. That is, the

bared portion 26a of the wire may be inserted from the front through the opening 28 in the base portion 29 of the terminal, to lie against the inclined surface 24 at one side of the shank of the binding screw, andmay be clamped the same as in the arrangement at the right of Fig. 2. Therefore, it will be clear that in this arrangement both back and front wiring is provided Without the necessity of looping or wrapping the .wire under the head of the screw, but in any case the wire may be so looped and clamped if desired.

In the modification shown in Figs. 3 to 7, the insulating body comprises. the two sections including the rear section 36 and the forward section 3 l,

which together form the chamber 32 for the switch elements, only one of which, the stationary contact 33, is shown. The front portion 3| of this insulating body is provided with a recess 34 opening through the rear wall thereof and also passing through the section so as to be open at the front. At the opposite ends of the recess it is provided with grooves 35 having inclined bottom walls 35. Mounted in this recess is the wiring terminal comprising in this case a base portion 37 corresponding generally with the base portion 29 of the first form, and into this base portion is threaded the binding screw 38 including the shank 39 extending into and rearwardly from the base portion. At opposite side edges of the base portion are side walls 40 which are arranged at substantially right angles to the base portion and have inclined side edges 4| which, when the terminal is seated in the recess 34, seat on the inclined bottom walls 36 of the grooves 35 and prevent the terminal from passing through the front open side of the reoess and. the terminal is retained in the recess by the body section 30, which closes the rear open side of the recess. The terminal also includes the inner wall 42 also bent up from one edge of the base portion, and the terminal contact 33-is connected to this wall.

Opposite to this wall 42 and between the side 7 walls 49 is a supporting wall 43 bent downwardly 0r rearwardly from the edge of the base portion 31, and providing a laterally curved inclined supporting wall 44 at one side of and adjacent the shank 39 of the terminal screw. This wall and the surface are inclined to the axis of the screw the same as is the surface 24 of the form of Figs. 1 and 2, and forms a supporting surface for the bared end 26 of the lead wire against which it is clamped by the free end portion of th shank 39 of the screw. It is also preferred to extend this wall 43 backwardly beyond the end of the shank of the screw and form it into a substantially cylindrical portion 45, into which the bared end 26 of the wire is inserted and by which the bared wire is guided to the clamping position between the shank 39 of the screw and the inclined surface 44. This tubular portion also acts as a support for the wire and prevents its being shifted laterally out of position by pressure of the screw. As this tubular portion extends below the rear face of the section 3! of the body, the rear section 30 of the body is provided with a recess 46 to receive this section, and the section 39 is also provided with an opening 4'! leading from its rear wall to the terminal recess and in substantial alignment with the inclined surface 44, so that the lead wire may be inserted from the rear for back wiring. The base portion 31 may also be provided with an opening 43 also in substantial alignment with the inclined surface 44 to permit insertion of the bared end of the lead wire from the front to the clamping position for front wiring if desired, similar to the arrangement shown at the left end of Fig. 2. It will be seen that this arrangement provides for both front and back wiring without the necessity of wrapping the lead wire around the screw under its head, but if desired the wire may be so wrapped around the screw and clamped in the usual way.

Fig. 8 shows a slightly different construction. In this arrangement, the terminal connection is substantially the same as, that shown in Figs. 3 and 4, except that the tubular extension 45 is omitted. In other words, the inclined wall 44 is cut off at about the level of the dividing surface 49 between the two sections 39 and 3! of the body, but it has the inclined clamping surface 44 curved laterally and arranged adjacent to the shank 39 of the screw, so that the bare wire 26 is clamped between the shank of the screw and the inclined surface 44, the same as in the arrangement of Fig. 3. The rear section 30a of the body is provided with a tapered opening 59 in alignment with the inclined surface for insertion of the lead wire from the back or rear of the device to the clamping position, and for guiding it to this position. The base portion 31 of the terminal may also be provided with the opening 48 in substantial alignment with the inclined surface so under its head, but, however, that this method of connection may be employed if desired. Also that; although the wire is not wrapped around the screw, it is effectively clamped and held and provides a very effective electrical connection. The wire may be set and clamped by merely inserting it to the clamping position and then settin up the screw, and it may be as easily and quickly detached if desired. With this arrangement, after the wire is clamped there i no loose end to contact other elements and form short circuits, as may often happen where the wire is wrapped around under the head of the screw, and also bending or shifting of the wire leading to the device does not loosen the binding screw,

as is often the case where the wire is wrapped around the screw.

Having thus set forth the nature of my invention, I claim:

1. A wire terminal connection for electrical wiring devices including a body of insulating material provided with a recess having inclined surfaces, a terminal mounted in said recess comprising a base portion and side walls at opposite edges of the base portion, one edge of each side Wall being inclined to seat on the inclined surfaces of the recess, a binding screw threaded in the base portion and including a shank between said side walls, another wall extending rearwardly from the base between the side walls and provided with a laterally curved surface at one side of th shank and inclined to the axis of the shank in position to support a lead wire clamped between the shank and said surface, and said body including a separate member over the open side of the recess to retain the terminal therein and provided with an opening leading from its rear wall to the recess for insertion of the bared end of a lead wire to the clamping position.

2. An electrical wiring terminal connection comprising a, metal plate forming a, base portion and provided with a threaded opening there- 6 through, a' binding screw threaded into said opening in the base portion including a head on one side of said base and a shank extending from the other side of the base, an integral wall extending in the same direction as the shank from one edge of the base portion at on side of the shank of the screw and inclined to the axi of this shank, said wall being provided with an inclined surface at one side of and adjacent the shank between which the bared end of a lead Wire may be clamped, and said inclined wall being provided with a tubular extension at its free end in substantial alignment with said inclined surface to guide the lead wire to clamping position. 3. A wire terminal connection for electrical wiring devices including a body of insulating material provided with a recess, a, terminal mounted in said recess comprising a base portion in the form of a metal plate provided with a threaded opening therethrough and side walls at opposite edges of the base portion integral therewith cooperating with walls of the recess to position the terminal therein, a binding screw threaded into said opening in the base portion and including a shank extending inwardly between the side walls,

an integral inclined laterally curved lead wire supporting wall extending inwardly from another edge of the base portion to a position at one side of the shank, and said latter wall being located adjacent to the shank and inclined to the axis thereof to support a lead wire clamped by said shank against said wall.

HARVEY HUBBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

